USGS Science⌕ Search
Home/Archive/USGS

USGS · 70274697

Status and trends in the Lake Superior fish community, 2025

Nicole M. Watson·Isabel I. Field·Jared Thomas Myers·Daniel L. Yule
View original source ↗Export metadata ↓

Abstract

The U.S. Geological Survey has conducted annual trawl surveys across Lake Superior since 1978 that describe trends in fish species occurrence and relative abundance to support fisheries science and management. In 2025, the Lake Superior fish community was sampled with daytime bottom and surface trawls at 72 nearshore stations in May and June and 36 offshore locations in July. Nearshore bottom trawls collected 63,005 fish represented by 30 species or morphotypes. The number of species collected at each location ranged from 1 to 13, with a median of 7.0 species. Estimated fish biomass density at individual stations ranged from <0.1 to 125.7 kg per ha with a lakewide mean of 7.6 kg per ha. Offshore bottom trawls collected 30,342 fish represented by 13 species or morphotypes. Estimated fish biomass density at individual stations ranged from 1.6 to 34.7 kg per ha with a lakewide mean of 9.1 kg per ha, which was the highest since the offshore survey began in 2011. Lakewide average numerical densities (fish per ha) of age-1 fish were 0.67 per ha for Bloater, 0.01 per ha for Cisco, 1.15 per ha for Kiyi, 0.95 per ha for Lake Whitefish, and 336.33 per ha for Rainbow Smelt. Surface trawling collected 1,562 larval Coregonus individuals which was the fewest Coregonus larvae collected in a whole lake survey since the larval fish survey began in 2014. Nearshore mean larval Coregonus numerical densities were 156 fish per ha in May and June 2025 and 21 fish per ha in July 2025. May mean surface water temperatures (6.1°C) were near the warmest for the period-of-record, while June (6.8°C) and July (10.0°C) were near average or below.

Explore related subjects

Report
90° N90° S · 180° W ← longitude → 180° E
Source-reported bounding extent: 46.39998810407942° to 49.03966846228119° latitude; -92.16156005859375° to -84.31732177734375° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Nicole M. Watson, Isabel I. Field, Jared Thomas Myers, Daniel L. Yule. 2026-03-31. Status and trends in the Lake Superior fish community, 2025. https://pubs.usgs.gov/publication/70274697

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Factors affecting benthic macroinvertebrate health in the City of Roanoke, Virginia, 2020–2023

Major waterways in the City of Roanoke (City) have failed to meet Virginia’s aquatic life designated use since 1996. Segments of the upper Roanoke River lack healthy benthic macroinvertebrate communities which prompted a total maximum daily load (TMDL) study by the Virginia Department of Environmental Quality (VDEQ) to identify the most probable stressor(s) causing the impairment. Excess fine sediment was identified as the most probable stressor impairing benthic macroinvertebrates on portions of the Roanoke River in 2006, and a watershed implementation plan published in 2016 required communities within the impaired watershed to implement projects that would reduce the load of fine sediment entering the Roanoke River. Additional benthic macroinvertebrate sampling and stream habitat assessments along the Roanoke River and Tinker Creek (a tributary to the Roanoke River that flows through the City) revealed continued impaired conditions, and subsequent stressor identification analysis was completed in 2023. Samples collected downstream of the City on the Roanoke River and Tinker Creek generally showed more impaired conditions relative to samples collected at locations upstream of the City. Based on this evaluation, sediment and sediment-bound polychlorinated biphenyls (PCBs) were identified as probable stressors while specific conductance, total nitrogen, and sediment metals were possible stressors in Tinker Creek; however, only a sediment TMDL target was identified to address impaired benthic macroinvertebrate communities. In the Roanoke River upstream of the Niagara Dam, sediment and total phosphorus were identified as probable stressors, sediment polycyclic aromatic hydrocarbons and sediment PCB were considered possible stressors; however, the TMDL target was only for total phosphorus. The City partnered with the U.S. Geological Survey (USGS) in 2016 to continuously monitor water quality and streamflow conditions on a major tributary of Tinker Creek, Lick Run, and by 2020, four similar monitoring stations were installed on the Roanoke River and Tinker Creek near the locations of benthic macroinvertebrate sampling. Monitored parameters included streamflow and/or gage height (water level), water temperature, pH, dissolved oxygen, specific conductance, and turbidity. Turbidity is a measure of the relative clarity of the water and was previously used to model suspended-sediment concentrations at the monitoring stations. The City also contracted Kirk Environmental, LLP (KE) to collect benthic macroinvertebrate samples and stream habitat assessments near the locations of the water-quality monitoring stations. Identified benthic macroinvertebrates were used to calculate the Virginia Stream Condition Index (SCI), a multi-metric index composed of eight biological attributes that represent elements of the structure and function of the benthic macroinvertebrate community that measure diversity, composition, and tolerance to pollution. Study objective: In this report, benthic macroinvertebrate samples and stream habitat assessment scores collected at four locations on the Roanoke River and Tinker Creek by KE and the VDEQ between 2020 and 2023 were compared to measured water-quality and streamflow conditions prior to sampling to evaluate patterns between benthic macroinvertebrate health, water quality, and hydrology.

Virginia↗